Two-order-parameter model of the liquid–glass transition. I. Relation between glass transition and crystallization

Tanaka, Hajime

doi:10.1016/j.jnoncrysol.2005.09.008

Cited by 88 publications

(105 citation statements)

References 154 publications

(299 reference statements)

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“…Taken together, the increase in N 6 , c 6 , and 6 suggest that short-range order increases during aging. Thus the dramatic structural and dynamic variation that occurs during aging clearly demonstrates that particles with short-range order are more stable than particle configurations with CN Þ 6, in agreement with Tanaka and co-workers [31], as well as with other theories that emphasize the importance of local structure [8,33].…”

supporting

confidence: 87%

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Irreversible Rearrangements, Correlated Domains, and Local Structure in Aging Glasses

et al. 2009

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supporting

confidence: 87%

“…For comparison, at t w ¼ 10 000 sec , 60% of all particles have CN ¼ 6, 31% have CN ¼ 5, 8% have CN ¼ 7, and 1% have CN ¼ 4. This distribution of locally ordered stable particle configurations provides a structural source for heterogeneous dynamics in glasses [31].…”

mentioning

confidence: 98%

Irreversible Rearrangements, Correlated Domains, and Local Structure in Aging Glasses

et al. 2009

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“…7 appears to be at variance with the results of a recent phenomenological model. 9,10 Further clarifications on the relevance of this theoretical approach to our simulated systems are required.…”

Section: T = 200mentioning

confidence: 99%

“…2,3,4 In particular, the emergence, upon supercooling, of slow domains, characterized by well-defined locally preferred structures, 5 has been recently identified as a possible origin of super-Arrhenius behavior, both in numerical simulations 6,7 and theoretical approaches. 8,9,10 Despite some efforts in this direction, the microscopic foundations of such a connection have been explored only to a limited extent. In fact, the relation between fragility and local order has been explicitly investigated only for monoatomic systems, 4,6,7 and operational schemes for a direct determination of locally preferred structures have not been tested yet for model supercooled liquids.…”

Section: Introductionmentioning

confidence: 99%

Understanding fragility in supercooled Lennard-Jones mixtures. I. Locally preferred structures

Coslovich

Pastore²

2007

The Journal of Chemical Physics

181

277

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We reveal the existence of systematic variations of isobaric fragility in different supercooled Lennard-Jones binary mixtures by performing molecular dynamics simulations. The connection between fragility and local structures in the bulk is analyzed by means of a Voronoi construction. We find that clusters of particles belonging to locally preferred structures form slow, long-lived domains, whose spatial extension increases by decreasing temperature. As a general rule, a more rapid growth, upon supercooling, of such domains is associated to a more pronounced super-Arrhenius behavior, hence to a larger fragility.

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“…1,3,4) Although the stability of the amorphous state can be improved by adding a large amount of excipients, intrinsic characteristics of the amorphous drugs must be understood well for the formulation design. Factors that influence the glass-forming ability 5,6) of compounds have been of great interest from that viewpoint. Although one suggestion is that it is correlated with fragility, 7) no clear relationship has been presented so far.…”

mentioning

confidence: 99%

Practical Approach for Measuring Heat Capacity of Pharmaceutical Crystals/Glasses by Modulated-Temperature Differential Scanning Calorimetry

et al. 2013

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A practical protocol to obtain accurate heat capacity values of pharmaceutical compounds using modulated-temperature differential scanning calorimetry was established. Three pharmaceutical compounds, acetaminophen, indomethacin, and tri-O-methyl-β-cyclodextrin were used as model compounds. Powder samples did not produce reproducible results, presumably due to inclusion of gas in gap of powders that influenced the measured heat capacity and thermal homogeneity in the sample. Thus, the amorphous characteristics were evaluated using quench-cooled samples. Crystalline samples were obtained by partially melting the sample to allow recrystallization using the residual crystal as a template. Optimum sample mass was about 10 mg. Use of too small sample size resulted in poor reproducibility due to localization of the sample in the pan, while too large size resulted in low heat capacity values probably because of heterogeneity of the sample temperature. The optimum modulation period was in the range of 60 s and 90 s, to which the ramp rates of 2°C/min and 1°C/min, respectively, were applied. The ramp amplitude was less significant in the evaluation. This information should help in comprehending basic characteristics of pharmaceutical compounds.Key words heat capacity; differential scanning calorimetry; amorphous; crystal Amorphous formulations are among the most promising options for developing poorly soluble drugs, because the amorphous state has a solubility advantage over crystals.

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Two-order-parameter model of the liquid–glass transition. I. Relation between glass transition and crystallization

Cited by 88 publications

References 154 publications

Irreversible Rearrangements, Correlated Domains, and Local Structure in Aging Glasses

Irreversible Rearrangements, Correlated Domains, and Local Structure in Aging Glasses

Understanding fragility in supercooled Lennard-Jones mixtures. I. Locally preferred structures

Practical Approach for Measuring Heat Capacity of Pharmaceutical Crystals/Glasses by Modulated-Temperature Differential Scanning Calorimetry

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